为了探究激光直接金属沉积316L不锈钢的表面粉末粘附工艺规律, 利用高速摄像机分析粉末粘附类型,采用单因素试验的方法, 定量研究了单道多层沉积中的送粉速率、送粉气流量和线能量密度对粉末粘附的影响规律。结果表明, 粉末粘附主要包括熔池熔液逸出和未熔粉末粘附两种类型; 随着送粉速率的增加和送粉气流量的减小, 薄壁件侧表面粉末粘附程度增加, 而粉末粘附程度则对激光线能量密度的变化不敏感;激光功率700W、扫描速率700mm/min、送粉量13.54g/min、送粉气流量14L/min、离焦量+22mm时, 激光直接金属沉积薄壁件表面粉末粘附较少。研究结果能够成为改善316L不锈钢增材制件表面质量的重要依据。

In order to investigate the surface powder adhesion process of 316L stainless steel by laser direct metal deposition, the type of powder adhesion was analyzed by high-speed camera. The influence of powder feeding rate, gas flow rate and linear energy density on powder adhesion in single-channel multilayer deposition was studied quantitatively by single factor test method. The results show that, adhesion powder mainly includes two types: molten solution escaping from molten pool and unmelted powder adhesion. With the increase of powder feeding rate and the decrease of powder feeding gas flow rate, the adhesion degree of powder on the side surface of thin-walled parts increases. However, the degree of powder adhesion is insensitive to the change of laser linear energy density. With laser power of 700W, scanning speed of 700mm/min, powder feeding rate of 13.54g/min, powder feeding gas flow rate of 14L/min and defocusing rate of +22mm, powder adhesion on the surface of thin-walled parts by laser direct metal deposition is less. The results can be used as an important basis for improving the surface quality of 316L stainless steel products.